/*
 * Copyright 2007 Google Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */
package java.util;

import com.google.gwt.lang.Array;

import java.io.Serializable;

/**
 * Resizeable array implementation of the List interface. <a
 * href="http://java.sun.com/j2se/1.5.0/docs/api/java/util/ArrayList.html">[Sun
 * docs]</a>
 *
 * <p>
 * This implementation differs from JDK 1.5 <code>ArrayList</code> in terms of
 * capacity management. There is no speed advantage to pre-allocating array
 * sizes in JavaScript, so this implementation does not include any of the
 * capacity and "growth increment" concepts in the standard ArrayList class.
 * Although <code>ArrayList(int)</code> accepts a value for the initial
 * capacity of the array, this constructor simply delegates to
 * <code>ArrayList()</code>. It is only present for compatibility with JDK
 * 1.5's API.
 * </p>
 *
 * @param <E> the element type.
 */
public class ArrayList<E> extends AbstractList<E> implements List<E>,
        Cloneable, RandomAccess, Serializable {

    private static native void setCapacity(Object[] array, int newSize) /*-{
        array.length = newSize;
    }-*/;

    private static native void splice(Object[] array, int index, int deleteCount) /*-{
        array.splice(index, deleteCount);
    }-*/;

    private static native void splice(Object[] array, int index, int deleteCount,
                                      Object value) /*-{
        array.splice(index, deleteCount, value);
    }-*/;

    private static native void spliceArray(Object[] array, int index,
                                           int deleteCount, Object[] values) /*-{
        array.splice.apply(array, [index, deleteCount].concat(values));
    }-*/;

    /**
     * This field holds a JavaScript array.
     */
    private transient E[] array = (E[]) new Object[0];

    /**
     * Ensures that RPC will consider type parameter E to be exposed. It will be
     * pruned by dead code elimination.
     */
    @SuppressWarnings("unused")
    private E exposeElement;

    /**
     * The size of the array.
     */
    private int size = 0;

    public ArrayList() {
    }

    public ArrayList(Collection<? extends E> c) {
        // Avoid calling overridable methods from constructors
        spliceArray(array, 0, 0, c.toArray());
        size = array.length;
    }

    public ArrayList(int initialCapacity) {
        // Avoid calling overridable methods from constructors
        assert (initialCapacity >= 0);
        setCapacity(array, initialCapacity);
    }

    @Override
    public boolean add(E o) {
        array[size++] = o;
        return true;
    }

    @Override
    public void add(int index, E o) {
        if (index < 0 || index > size) {
            indexOutOfBounds(index, size);
        }
        splice(array, index, 0, o);
        ++size;
    }

    @Override
    public boolean addAll(Collection<? extends E> c) {
        Object[] cArray = c.toArray();
        int len = cArray.length;
        if (len == 0) {
            return false;
        }
        spliceArray(array, size, 0, cArray);
        size += len;
        return true;
    }

    public boolean addAll(int index, Collection<? extends E> c) {
        if (index < 0 || index > size) {
            indexOutOfBounds(index, size);
        }
        Object[] cArray = c.toArray();
        int len = cArray.length;
        if (len == 0) {
            return false;
        }
        spliceArray(array, index, 0, cArray);
        size += len;
        return true;
    }

    @Override
    public void clear() {
        array = (E[]) new Object[0];
        size = 0;
    }

    public Object clone() {
        return new ArrayList<E>(this);
    }

    @Override
    public boolean contains(Object o) {
        return (indexOf(o) != -1);
    }

    public void ensureCapacity(int capacity) {
        if (capacity > size) {
            setCapacity(array, capacity);
        }
    }

    @Override
    public E get(int index) {
        checkIndex(index, size);
        return array[index];
    }

    @Override
    public int indexOf(Object o) {
        return indexOf(o, 0);
    }

    @Override
    public boolean isEmpty() {
        return size == 0;
    }

    @Override
    public int lastIndexOf(Object o) {
        return lastIndexOf(o, size() - 1);
    }

    @Override
    public E remove(int index) {
        E previous = get(index);
        splice(array, index, 1);
        --size;
        return previous;
    }

    @Override
    public boolean remove(Object o) {
        int i = indexOf(o);
        if (i == -1) {
            return false;
        }
        remove(i);
        return true;
    }

    @Override
    public E set(int index, E o) {
        E previous = get(index);
        array[index] = o;
        return previous;
    }

    @Override
    public int size() {
        return size;
    }

    @Override
    public Object[] toArray() {
        return Array.cloneSubrange(array, 0, size);
    }

    /*
    * Faster than the iterator-based implementation in AbstractCollection.
    */
    @SuppressWarnings("unchecked")
    @Override
    public <T> T[] toArray(T[] out) {
        if (out.length < size) {
            out = Array.createFrom(out, size);
        }
        for (int i = 0; i < size; ++i) {
            out[i] = (T) array[i];
        }
        if (out.length > size) {
            out[size] = null;
        }
        return out;
    }

    public void trimToSize() {
        setCapacity(array, size);
    }

    @Override
    protected void removeRange(int fromIndex, int endIndex) {
        checkIndex(fromIndex, size);
        if (endIndex < fromIndex || endIndex > size) {
            indexOutOfBounds(endIndex, size);
        }
        int count = endIndex - fromIndex;
        splice(array, fromIndex, count);
        size -= count;
    }

    /**
     * Used by Vector.
     */
    int capacity() {
        return array.length;
    }

    /**
     * Used by Vector.
     */
    int indexOf(Object o, int index) {
        for (; index < size; ++index) {
            if (Utility.equalsWithNullCheck(o, array[index])) {
                return index;
            }
        }
        return -1;
    }

    /**
     * Used by Vector.
     */
    int lastIndexOf(Object o, int index) {
        for (; index >= 0; --index) {
            if (Utility.equalsWithNullCheck(o, array[index])) {
                return index;
            }
        }
        return -1;
    }

    /**
     * Used by Vector.
     */
    void setSize(int newSize) {
        setCapacity(array, newSize);
        size = newSize;
    }
}
